1. Field of the Invention
The present invention is concerned generally with an apparatus and method for bioremediation of hydrocarbon-contaminated objects, including biodegradation of petroleum products contaminating such objects. The present invention further relates to an apparatus for cleaning and the microbial bioremediation of hydrocarbon-contaminated objects, featuring a method for cleaning and the microbial bioremediation of hydrocarbon-contaminated objects, as well as the microbial bioremediation of the hydrocarbon-contaminate removed from the object. The method of the present invention uses microbial compositions which are environmentally friendly and which typically decompose hydrocarbons without polluting the environment.
More specifically, the present invention provides an efficient reservoir, acting as a biochamber, to accelerate the bioremediation of oil/grease contamination encountered in parts used, for example, in the automobile, aircraft and small engine industries where numerous objects are typically contaminated with oils and/or greases. The present invention also provides an environmentally friendly enhanced bioremediation method using oil and grease-degrading bacteria for cleaning objects which have been hydrocarbon contaminated.
The invention further relates to a method for cleaning hydrocarbon-contaminated objects by degrading the hydrocarbon constituents of petroleum products in any environment. The present invention advances state-of-the-art technology in the area of pollution control through the process of enhanced bioremediation.
2. Description of Related Prior Art and Information
This invention relates to an apparatus and method for enhancing bioremediation of hydrocarbon-contaminated objects such as car and airplane parts, and parts such as those encountered in industrial machinery, which from time to time need cleaning and/or repair. The method of the present invention takes advantage of certain microorganisms which are capable of degrading alkanes and other petroleum derived hydrocarbons, including greases as well as hydrocarbons, having unsaturation and multiple unsaturated sites, such as double and triple bonds e.g., aromatic hydrocarbons, alkenes, alkynes and cycloaliphatic compounds.
Hydrocarbons such as crude petroleum and petroleum-derived materials are typically characterized as a complex mixture of straight chain and branched alkanes or alkenes, saturated ring compounds and aromatic compounds. Crude petroleum products are also known to contain small amounts of sulfur, nitrogen, or oxygen covalently attached to the various hydrocarbon chains. Industrial products such as gasoline, kerosene, burner fuel oil, diesel oil, gas turbine oil, aviation fuels, lubricating oils and hydrocarbon greases are examples of petroleum-derived products. The widespread use of the above petroleum-derived products has a concomitantly associated environmental cost related to contamination of industrial parts, contamination of soils, or accidental spills or releases.
Cleanup operations of petroleum pollution are both physically and technically difficult and a number of potential solutions for bioremediation of petroleum pollution have been attempted or proposed. For example, current cleanup practices include: 1) physical removal of the polluting petroleum by use of absorption media; 2) dispersal using detergents; 3) burning; 4) microbial degradation under ideal conditions; 5) agglomeration of oil on water and sinking to the floor of the water body; and 6) use of organic chemicals, such as kerosene-based dispersants, to dissolve and disperse the oil. Each of the above measures has its own set of special environmental and technical considerations.
In years past, the generally accepted procedure for controlling environmental damage due to hydrocarbon contamination was to ship the undesirable contaminants to a secure landfill. However, given the decreasing availability of landfills willing to accept hazardous wastes, the high cost of detailed manifesting of the generated waste stream, the high cost of transport and removal of contaminants, and the potential exposure to liability associated with off-site transport and disposal, landfill disposal of objects contaminated with hydrocarbons is becoming an increasingly unacceptable and costly means for handling these materials.
An important procedure for reducing the amount of hydrocarbon contamination in the environment is known as bioremediation. The process of bioremediation relies on the hydrocarbon-degrading abilities of biologic materials such as bacteria, saprophytes, bacterial enzymes or saprophytic enzymes to degrade the hydrocarbon in the contaminated objects. The hydrocarbon degrading biologic materials are often naturally present in contaminated materials and, given sufficient time, can naturally degrade the hydrocarbon contaminants. However, this natural degradation process can often be promoted by directly adding biologic materials to the contaminated materials in an amount sufficient to degrade the hydrocarbons, or by encouraging the proliferation of hydrocarbon-degrading microorganisms, either naturally present, or present as a result of inoculation. Proliferation of hydrocarbon-degrading microorganisms can also be encouraged by the addition of nutrients, or by adjusting the conditions to favor growth of the desired microorganisms referred to as "enhanced bioremediation."
Bioremediation of hydrocarbon contamination is favored over removal or chemical treatment because of the lower cost, proven effectiveness, and the ability for on-site reduction of hydrocarbon contamination. However, these advantages can be outweighed by the substantial length of time necessary for bioremediation. Under optimum conditions, months or years may be required to reduce the levels of hydrocarbon contamination to a desired level. This disadvantage has greatly limited the potential use of bioremediation to reduce hydrocarbon contamination of materials.
The optimum combination of properties for a method, apparatus, and composition effective in the degradation of hydrocarbons, particularly one based in the utilization of microorganisms, is such that:
(1) the method, apparatus and composition must demonstrate acceptable efficacy in actual non-laboratory environments, yet be in such a form as to itself be non-toxic and non-deleterious, and in such a form so as not to generate deleterious products or chemicals harmful to, or befouling to the environment;
(2) the method and composition must be long-acting and rapid in the onset of its initial activity and require no further support or sustaining activities after initiation;
(3) the method and composition must be self-sustaining, so as to require no additional provision for nutrients or other supporting chemicals;
(4) the method and composition, together with the degraded, solubilized crude hydrocarbon product, must be self-dissipating after the substantial completion of the degradation of the hydrocarbon constituents, so as to require no retrieval from the environment and disposal; and
(5) the method, apparatus and composition must be easy to effect and manufacture, while safe to personnel using the composition or carrying out the process, at all stages and times in its preparation and use.
U.S. Pat. No. 3,152,983 to Davis, et. al., discloses the microbial disposal of oily wastes. The method of Davis, et. al., is designed for large industrial waste separation and disposal, beginning with an oil water separator. The method suggests processing one batch at a time and is not a continuous, on-going method which preserves the microbes.
U.S. Pat. No. 3,838,198 to Bellamy, et. al., is directed at conditioning raw waste input for digestion by thermophylic aerobic microorganisms. The process is geared towards animal waste and is not a self-perpetuating process.
U.S. Pat. No. 3,871,956 to Azarowicz features a method for cleaning accidental oil spills on water or in soil. The method of the '956 patent does not utilize temperature or oxygen controls and is not a self-perpetuating process.
U.S. Pat. No. 3,899,376 to Azarowicz features microbial action for cleaning industrial effluent. This Azarowicz patent does one batch at a time, using a new microbial solution in each bath, however it is not a continuous accelerated method.
U.S. Pat. No. 4,401,569 to Jhaveri, et. al., describes a method and apparatus for treating hydrocarbons and halogenated hydrocarbon-contaminated ground and ground water.
U.S. Pat. No. 5,494,580 to Baskys, et. al., relates to a method for decontamination of a hydrocarbon-polluted environment by the use of certain bacterial compositions.
The above prior art is silent regarding the apparatus and bioremediation method of the present invention. Accordingly, there is a need for a process that will rapidly decontaminate hydrocarbon-contaminated objects in an efficient and environmentally acceptable manner. That need is now satisfied by the invention described below.